Case Summary
Did you know that Second Amendment protected rights cover, not just firearms, but also knives? Andrew Teter and James Grell are law-abiding residents of Hawaii who want to own folding pocket-knives with split handles, also known as butterfly knives. But this type of knife was banned years ago by the State of Hawaii. MSLF filed an amicus brief with the Ninth Circuit Court of Appeals in support of Andrew and James, arguing that Hawaii’s prohibition violates their Second Amendment protected rights to keep and bear arms, since the word “Arms” applies to all arms, including knives and other bladed weapons.
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Case History
Butterfly knives were banned years ago in Hawaii, in what was little more than a reaction to old movie images that unfairly associated them with gang and other illegal activity—à la “West Side Story.” The plaintiffs in this case, Andrew Teter and James Grell, are asking the courts to acknowledge that the Second Amendment also protects the right to keep and bear, not just guns, but knives too.
While Hawaii has broad power to make policy decisions for its residents, Hawaii lacks the authority to completely ban the manufacture, sale, transfer, possession, or transportation of butterfly knives.

Today, firearms are the first thing most of us think of when the term “Arms” is used, for understandable reasons. But a review of the historical record makes clear that the Framers of the Constitution had a much broader definition of the word “Arms” in mind, given the times and circumstances in which they lived. Rudimentary firearms existed then, but were still in their infancy, technology-wise. Battles were fought and personal security was maintained using an array of Arms, including swords, knives, hatchets, and bayonets.
Hawaii’s prohibition on butterfly knives is based on the false premise that folding pocket-knives with split handles, more commonly known as butterfly knives, are only associated with ne’er-do-wells and criminals; not because the knives themselves are inherently more dangerous or more commonly used in crime.
Not only is the premise behind the ban false, but it’s also beside the point if we take an honest look at the original meaning of the term “Arms” in the Second Amendment.
Mountain States Legal Foundation filed an amicus curiae brief on August 28, 2020. The brief supports Andrew Teter and James Grell, who are challenging the constitutionality of Hawaii’s ban on “butterfly knives,” on the grounds that it violates their Second Amendment-protected right to keep and bear arms.